1. Field of the Invention
The present invention relates to a hydrogel, a preparation method thereof, and a pH sensor comprising the same, and more particularly, to a hydrogel, which can substitute for conventional pH paper, is continuously usable, can be used in various applications, and reversibly changes color depending on the pH of a sample, and to a pH sensor comprising the same.
2. Description of Related Art
A technology for measuring or sensing pH is required in various technical fields. To measure or sense pH, pH paper has been widely used. The pH paper is easily available and is simple to use, but can be limitedly used for samples containing at least a certain amount of moisture or liquid-state samples, and is difficult to use for the monitoring of air pollution, the measurement of pH of moisture-free samples, the monitoring of leakage of strong acids or strong bases, etc. In addition, the pH paper is not recyclable once used, and is difficult to use in various fields. Thus, the pH paper is insufficient to function as a sensor.